Nanosphere, Inc. is utilizing gold nanoparticle probes to develop a novel chip-based DNA detection technology that does not require target amplification. Because of their ultra-high sensitivity, exquisite specificity, low cost and remarkable stability, the gold nanoparticle probes could define a new industry standard for nucleic acid testing. The current proposal describes two objectives that will significantly broaden our SNP detection capability. First, we will continue developing a rapid test to identify simultaneously SNPs in three genes involved in hypercoagulation disorders [factor V (1691 G->A), prothrombrin (20210 G->A) and MTHFR (677 C->T)]. Phase I feasibility studies have demonstrated key capabilities of the system including detection and SNP discrimination in un-amplified genomic DNA. In Phase II, the individual genes will be integrated into a single test. The system requirements will be optimized and internally validated. In the second objective, strategies to further improve sensitivity and specificity will be evaluated with the goal of increasing our multiplex capability in PCR-less detection. Success in meeting these goals will provide clinical laboratories with a simple test to assess genetic risk factors in hypercoagulation. Further, it will provide the necessary framework for future development of SNP detection tests in genomic DNA for other medically relevant genes.